The present invention relates to a foldable knife structure in which the knife blade may be automatically controllably unfolded in a stage by stage manner for convenience and safety in use.
There are various kinds of knives with different dimensions and patterns for different uses. For example, a chopper knife is used to cut meat or vegetable, a paper knife is used to cut paper or pare a pencil, a spring knife is used in mountaineering, a hatchet knife is used outdoors, a clasp knife is portable, etc. With respect to a spring knife, a blade is quickly unfolded for use by means of a resilient member. The conventional spring knife is generally designed so that one side of the grip of the knife is pressed to unfold the blade from the other side of the grip into an extended state. Alternatively, the back of the knife may be depressed to unfold the blade.
As shown in FIG. 1, each of the above described conventional knives has a knife grip 2 for receiving the blade 1. When not used, the blade section 10 of the knife blade is hidden in the grip 2 for easy carrying. However, in actual use of the knife, some shortcomings exist in conventional knives as follows:
1. When folding the knife blade into the grip, only a small part of the knife back is exposed to the exterior. Therefore, it is not easy to extend the knives blade. In some knife, the face of the blade near the back thereof is formed with a shallow groove for conveniently drawing out the blade. However, since the blade is made of metal and has a polished face, the shallow groove rends it difficult for a user to easily unfold and extend the blade. PA1 2. The convent ional knife structures lack safety designs for protecting the user, especially the user's hand, from being injured. Especially, with respect to a spring knife, the blade is quickly unfolded by a resilient member. This often leads to accidental cutting or stabbing of the user. Moreover, the resilient member of the spring knife is often designed with a poor position and structure so that after being extended, the blade cannot be quickly and safely folded.